1. Field of the Invention
The present invention relates to a process for producing aromatic nitrile and more particularly to a process for efficiently producing aromatic nitriles by reacting aromatic halides substituted by a nitro group in the ortho position relative to the halogen atom with cuprous cyanide and alkali cyanides in a polar solvent.
2. Description of the Related Art
A method of preparation of aromatic nitriles by reacting aromatic halide and cuprous cyanide is well known as the Rosenmunt von Braun reaction As one example, Chemical Abstracts, 59: 6319b describes a method of synthesizing 2-chloro-6-nitro-benzonitrile by reacting 2,3-dichloronitrobenzene and cuprous cyanide at a high temperature in a polar solvent, e.g., pyridine or dimethylformamide.
This method, however, needs more than an equimolar amount of cuprous cyanide relative to aromatic halide and further has disadvantages in that the resultant nitrile product forms an insoluble complex with the copper compound. thereby making difficult separation and the purification thereof. Moreover, it has a disadvantage in that an operation for removal of copper salts in the product by washing with ammonia water or water is complicated.
For this reason, a method in which the copper compound is oxidized by adding a divalent copper salt, or a method in which the nitrile-copper complex is decomposed by adding an excess amount of cyano compound has been employed.